Tonight sees the return of New Girl and The Mindy Project on Fox, and besides sharing the same hour on the same network, the two also have something else in common: A main couple that has been driving the series. Last season, New Girl put Nick and Jess together with results that weren’t quite disastrous, but it sure took a lot of air out of the sitcom’s sails. This season, The Mindy Project will begin with their main couple, Mindy and Danny, together, and we will see if Mindy Kaling will be able to navigate that better than Elizabeth Meriwether.

The reality, unfortunately, is that while many shows can survive — and even thrive — once the main couple has gotten together, they’re rarely the same. The will-they-won’t-they simply doesn’t work as well once the couple has consummated the relationship. The constant breaking up eventually only brings frustration (exception, Felicity, but a viable third option is necessary).

Hopefully, Kaling has figured it out. My advice: Go the Andy and April route. Downplay the relationship — make it a secondary plot element — and keep the focus elsewhere.

Here’s ten series that never fully recovered after the main couple got together:

Dave and Alex in Happy Endings — Alex stood Dave up at the altar in the pilot episode, and there was some tension over whether they’d get back together, until the finally did in season three to the surprise of everyone, mostly because nobody wanted it (and they finally broke up again).

Nick and Jess in New Girl — It was so much fun in season two watching these two fumble around their sexual chemistry, but it all but vanished in season three once they finally got together. Season four, thankfully, will begin with them apart, hopefully permanently. Please do not attempt to play the will-they-won’t-they and jealousy plotlines.

Ross and Rachel in Friends — Moonlighting may have originated this trope, but Ross and Rachel popularized it more than any other couple in television history. Unfortunately, their relationship — and Friends as a whole — was all downhill after Rachel kissed Ross after witnessing what he’d done for her at prom. This was peak Friends. It was never quite the same.

Chuck and Sarah in Chuck — Chuck was an entertaining, delightful action-spy series that hummed along while Chuck and Sarah flirted incessantly with each other (at least when Chuck wasn’t weirdly flirting with his sister). Once Chuck and Sarah got together, however, the series fell into a rut as each episode centered around the next stage of their relationship: Moving in together, buying a ring, proposing, the bachelor party, etc., etc. It became predictable and numbing.

Leslie and Ben on Parks and Recreation — Such an amazing, lovely couple and Greg Daniels has managed their relationship better than most sitcoms have, and it was perfect right up until the wedding. Still, it’s not quite the same since the two got together — it feels too settled. The spark isn’t quite there anymore. That said, Parks has handled April and Andy’s relationship absolutely perfectly. There is your model for future sitcoms.

D10 and Rose in Doctor Who — So much of this series throughout the decades was about the asexual nature of the Doctor, and the series could really only create a strong romantic relationship once every ten or 15 years. D10 and Rose was perfect, and not so coincidentally, those were the very best years of the modern Who. It’s managed some great episodes since, and there was some interesting sexual tension with River Song and even some fun flirtation with Amy Pond, but it’s never been the same, and may never be the same again.

Luke and Lorelai in Gilmore Girls — Once they got together in season five, it didn’t quite feel the same, almost as though they were not a couple that ever should’ve gotten together. They should have remained permanently an almost-couple, or a Winnie and Kevin couple that realized that they were better as best friends (losing Amy Sherman Palladino in the final season didn’t help matters).

Juliet and Shawn on Psych — It’s probably no coincidence that ratings for the USA Network show began to dwindle once Juliet and Shawn got together (I was among those who drifted away). The show had already begun to lose steam, but those two getting together took all the air out of the series.

Ted and Robin, How I Met Your Mother — Interestingly, the will-they-or-won’t-they between Ted and Robin nearly ruined the series (and eventually did in the finale), but the will-they-won’t-they between Robin and Barney managed to keep it afloat (again, until the finale).

Jim and Pam in The Office — It was such a perfect relationship, even after they’d gotten married, and I would’ve been perfectly content with a boring relationship until the series ended. Unfortunately, the writers decided to shake things up, convinced that they needed to create some unnecessary tension in their marriage. We never need to speak of the final season again.

Dustin is the founder and co-owner of Pajiba. You may email him here, follow him on Twitter, or listen to his weekly TV podcast, Podjiba.